fix: product id should be required for replies too

schema.gql

@@ -7,7 +7,7 @@ type Comment {
   id: ID!
   postedAt: DateTime!
   content: String!
-  productId: ID
+  productId: ID!
   parentId: ID
   replies: [Comment]
   userId: ID!

src/modules/comment/comment.entitiy.ts

@@ -45,9 +45,9 @@ export class Comment extends BaseEntity {
 		}
 	)
 	product!: Product;
-	@Field(() => ID, { nullable: true })
-	@Column({ nullable: true })
-	productId?: number;
+	@Field(() => ID)
+	@Column()
+	productId!: number;
 
 	@ManyToOne(
 		type => Comment,

src/modules/comment/comment.service.ts

@@ -61,7 +61,7 @@ export class CommentService {
 		parentId?: number
 	): Promise<Comment> {
 		if (parentId) {
-			return await this.addReply(parentId, content, userId);
+			return await this.addReply(parentId, content, userId, productId);
 		}
 
 		const newComment = new Comment();
@@ -88,12 +88,14 @@ export class CommentService {
 	private async addReply(
 		parentId: number,
 		content: string,
-		userId: number
+		userId: number,
+		productId: number
 	): Promise<Comment> {
 		const reply = new Comment();
 		reply.parentId = parentId;
 		reply.content = content;
 		reply.userId = userId;
+		reply.productId = productId;
 		const newReply = await this.commentRepository.save(reply);
 		const { parent } = await this.commentRepository.findOneOrFail(
 			{ id: newReply.id },